7th Mar 2021

Melatonin, Sleep, and Immunity

Chances are we’ve all heard of the word 'Melatonin' – the hormone related to sleep and sleepiness. We also know how important sleep is for our immune system, and our physical, mental, and emotional well- being.

What's interesting is that melatonin has now been the subject of several scientific studies reviewing its potential role in the COVID-19 treatment. There are indications that due to its anti-inflammatory, antiapoptotic, immunomodulatory, and powerful antioxidant properties, melatonin may potentially help as a treatment for viral infections to help reduce disease severity. However, to be clear, clinical data is very limited, and there is currently nothing definitive in the science showing that melatonin can protect against the most serious effects of COVID-19. (Breus, 2020; El-Missiry et al., 2020; Reiter et al., 2020; Shneider et al., 2020; Zhang et al., 2020).

What is Melatonin, and how does it work?

Melatonin is a hormone naturally produced by many organs in our body, but it is primarily secreted from the pineal gland – the pebble sized gland in the middle of the brain. Melatonin regulates sleep through its influence over the body’s bio clock and sleep-wake cycles. The brain receives light and dark cues through the retina of the eye, which then increases the production of melatonin through the pineal gland.

Melatonin fosters better sleep by regulating our body’s response to light; cuts down the time it takes to fall asleep, and thereby improves our sleep quality and duration. Melatonin production rises in response to darkness, and is suppressed by exposure to light. It follows a daily 24-hour sleep-wake cycle, also known as our body’s circadian rhythm, or internal clock.

Generally, melatonin levels begin to rise significantly at around 9 p.m. and peak sometime during the overnight, falling to their lowest levels in the morning. Thus, the rise and fall of melatonin production over the 24-hour cycle facilitates conditions for us to stay awake and alert during the day, and sleepy as night falls - to ensure a good, restful night’s sleep.

Increasing our body's natural melatonin production for better sleep and immunity

Our body can produce melatonin on its own, but sometimes stressful, long hours at work, poor sleep habits, old age and illness, chronic stress, or even a one-off stressful life event may hamper the hormone’s production. Following are some ways we can boost our body's melatonin production naturally:

1) Keep it dark at bedtime: Light suppresses melatonin production, so any exposure to artificial lights during bedtime, particularly blue light, will block melatonin production. Sources of blue light include digital screens, electronic devices, fluorescent and LED lighting.

2) Consistency and regularity: Our 24 hour sleep-wake cycle works best with regular sleep habits, such as going to bed at night and waking up in the morning at around the same times from day to day, including weekends. This keeps our internal body clock attuned, thus minimising sleep irregularities.

3) Get some sunlight: Sleep is more restorative and effective when our circadian rhythms are in-sync – our body overall functions better, which means our capacity to produce melatonin, is higher. A great way to adapt to the 24 hour day and attune our circadian rhythms is by getting plenty of sun exposure during the day, especially early morning and afternoon.

4) Stay positive: When you’re worried about things going on in your life, you may find yourself awake in the middle of the night, unable to go back to sleep- way too many things playing up in your mind, keeping you awake, robbing you of your precious sleep. It makes perfect sense -serotonin, our happy hormone, is a chemical precursor to melatonin. Our body needs serotonin from the pineal gland in order to produce melatonin. The best way to increase serotonin levels is by exercising outdoors, exposing yourself to plenty of sunlight, especially early in the morning, and staying in a positive frame of mind as much as you possibly can (Young, 2007).

5) Avoid adrenaline before bedtime: Adrenaline is a hormone released into the body of someone feeling extreme emotions, which causes the person to have more energy. Watching intense TV programs or movies before bedtime or engaging in stressful activities such as family arguments, as well as listening to, or reading something stressful, will make our body produce adrenaline, when the body needs to be producing melatonin instead, making it harder for us to go to sleep.

6) Foods that naturally contain melatonin: Eating certain foods before bed may also help boost our melatonin production; these include rice and cereals, and fruits such as cherries, bananas, grapes, and plums.


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Reiter, R. J., Sharma, R., Ma, Q., Dominquez-Rodriguez, A., Marik, P. E., & Abreu-Gonzalez, P. (2020). Melatonin Inhibits COVID-19-induced Cytokine Storm by Reversing Aerobic Glycolysis in Immune Cells: A Mechanistic Analysis. Medicine in drug discovery, 6, 100044. Advance online publication.

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Shneider, A., Kudriavtsev, A., & Vakhrusheva, A. (2020). Can melatonin reduce the severity of COVID-19 pandemic?. International reviews of immunology, 1–10. Advance online publication.

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Zhang, R., Wang, X., Ni, L., Di, X., Ma, B., Niu, S., Liu, C., & Reiter, J.R. (2020). COVID-19: Melatonin as a potential adjuvant treatment. Life sciences, 250, 117583.

Disclaimer – This information is general in nature. We are not medical professionals or doctors, and we don’t claim to be one, so if you have any medical conditions, please contact your nearest medical clinic and seek individualised treatment with your medical care provider.

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